In the technical field of liquid crystal display, thin film transistor liquid crystal displays (TFT-LCDs) belong to a main kind of flat-panel display devices.
According to different employed light sources, liquid crystal displays are classified into transmissive liquid crystal displays, reflective liquid crystal displays and transflective liquid crystal displays. Among them, a transflective liquid crystal display has both advantages of a transmissive liquid crystal display and of a reflective liquid crystal display, and can be used both indoors and outdoors. Moreover, a transflective liquid crystal display utilizes a backlight and ambient light simultaneously and has low-power consumption, and is widely used in display devices of portable and mobile electronic products.
Transflective liquid crystal displays, in which the liquid crystal molecules are blue-phase liquid crystal, in virtue of rapid response speed of the components and good quality of displayed images, have attracted lot of attention. Blue-phase liquid crystal can change its isotropic refractive index into an anisotropic refractive index, based on the magnitude of the voltage applied thereto. With blue-phase liquid crystal, an alignment film is not required to be provided in a display panel, which makes the implementation procedure simple; further, blue-phase liquid crystal realizes a faster response speed.
The existing transflective blue-phase liquid crystal display panel is a lateral electric field mode liquid crystal display panel, in which electrodes are provided on a same substrate of the transflective blue-phase liquid crystal display panel to generate for example an In-Plane Switching (IPS) mode electric field, which is also called as a lateral electric field, and such an electric field needs a high driving voltage of about 20˜30V for normal image display. Besides, lateral electric field electrodes are provided on an array substrate, and therefore stronger electric field intensity occurs near the array substrate and weaker electric field intensity occurs near the color-filter substrate. This results an uneven distribution of the electric field in the liquid crystal layer, which has an influence on the displayed image of the device.
In addition, the existing lateral electric field mode transflective blue-phase liquid crystal display panel has a step provided between a light transmissive region and a light reflective region, to balance phase retardation respectively produced when light passing through the transmissive region and the reflective region. But the implementation is difficult.
In summary, the existing transflective blue-phase liquid crystal display panel needs a high driving voltage, and has difficulty in balancing phase retardation respectively produced when light passing through the transmissive region and the reflective region.